Process for making yogurt cream cheese, and the resulting products

ABSTRACT

A process for making a yogurt cream cheese product comprising steps of: providing a milkfat fluid having an initial butterfat content level; pasteurizing the milkfat fluid to yield a cream cheese precursor; providing a yogurt, and combining the yogurt with the cream cheese precursor to yield a combined precursor; and homogenizing and acidifying the combined precursor; yielding a yogurt cream cheese product. A yogurt cream cheese product comprising between about 8% by weight and about 35% by weight of total butterfat; the yogurt cream cheese product comprising between about 10% by weight and about 40% by weight of yogurt, having a viscosity between about 1,000,000 centipoises and about 3,000,000 centipoises at a temperature of about 74° F.; and yielding less than about 1% syneresis by weight after 15 hours at about 74° F. to about 75° F.

FIELD OF THE INVENTION

The present invention relates to the field of processes for making creamcheeses, and the resulting products. More particularly, the presentinvention relates to processes for making yogurt cream cheese productsthat comprise yogurt and retain whey from the milkfat fluid used to makethe products. These yogurt cream cheese products combine the desirabletexture and mouth feel of cream cheese, having a dramatically improvedflavor due to retained whey, with the additionally desirable taste andactive culture bacteria health benefits of yogurt.

BACKGROUND OF THE INVENTION

Cream cheese products are ubiquitous in modern diets. They generallyhave a smooth texture and a bland, unremarkable flavor. Spreadabilitymakes cream cheese convenient to use, which is the primary basis for itschoice by consumers over other firmer cheeses and the reason for itshigh volume consumption as a topping, for example on breads includingbagels. In the classic method for making cream cheese, a pasteurizedmilkfat fluid such as cream, having a butterfat content generallybetween about 34.5% by weight and 50% by weight, is the primary rawmaterial. This milkfat fluid is subjected to thorough digestion bylactic acid—producing bacteria, homogenized, and clotted by enzymes oracidification. The milkfat fluid is thus transformed into a solid phasereferred to as the curd, and a liquid phase referred to as the whey.Most of the butterfat content of the milkfat fluid is retained in thecurd; and significant protein content, having nutritional value and muchof the desirable potential flavor, remains in the whey. At such a point,the curd is further processed into the desired cream cheese product, andthe whey is discarded, along with its flavor. As a result, cream cheesetypically has a bland, dull, virtually unnoticeable taste. The retentionof liquid whey in the curd is a problem in itself, as the liquidgradually leaks out of the curd in an unappealing and ongoing separationthat is called syneresis. In addition, large scale cream cheeseproduction generates corresponding quantities of often unusable whey,which thus becomes a waste expense and environmental detraction unlesssome other use can be found for it.

The minimum butterfat content for cream cheese is 33% by weight. It is apervasive goal in the human diet to consume less fat; and the relativelyhigh butterfat content of a typical cream cheese is not helpful inachieving this goal. Countless attempts have been made to make low-fatcream cheese products, but the resulting cheese products have failed dueto unacceptable taste and poor texture.

Yogurt, another highly prevalent milk—derived product, has an entirelydifferent consistency than cream cheese, as well as a fundamentallydifferent flavor. In illustration, yogurt is considered to be a food,whereas cream cheese is considered to be a condiment. For example,yogurt, unlike cream cheese, is not a popular topping for bread productssuch as bagels. On the other hand, yogurt has a robust, desirableflavor. Yogurt also is typically lower than cream cheese in butterfat,cholesterol and sodium, and higher in protein.

A health-conscious consumer might well make the simple observation thatnonfat yogurt has a robust, desirable flavor, find the concept ofcombining yogurt and cream cheese to be desirable, and thus attempt tocombine these products together. However, due to the disparateproperties of cream cheese and yogurt, including for example theirdiffering consistencies, water content, and food chemistries, thecombination of cream cheese and yogurt in mutually appreciableproportions only generates a runny mess. A consumer might then attemptto drain the liquid from the solid phase of the yogurt before combiningin the cream cheese, thereby discarding whey from the yogurt.

Producing a cream cheese having an appealing consistency and utility,for example as a spreadable topping, is not possible by mixing creamcheese and yogurt without also adulterating these ingredients either bydiscarding whey from the yogurt or cream cheese, or by addingsubstantial proportions of gums and processed milk byproducts such asmilk protein concentrate, whole milk protein, whey protein concentrate,casein, Baker's cheese, yogurt powder, and dry cottage cheese curd. Atthat point, the product is no longer cream cheese but a processed cheesespread, typically having inferior texture and nutritional value, and aflavor that is either bland or even mildly unpleasant. Efforts have alsobeen made to produce so-called low-fat cream cheese, but again theresulting product has offered a bland, unremarkable and potentiallyunpleasant flavor. Hence, despite the broad popularity of cream cheese,its use typically entails consumer acceptance of a minimum butterfatcontent of 33% by weight, along with high cholesterol and sodium, and abland, unremarkable taste.

Accordingly it would be highly desirable to provide a process for makingan improved cream cheese product from a milkfat fluid, having theconsistency of high-milkfat cream cheese but combining the desirableflavor and nutritional benefits of yogurt with the flavor of wheyretained from the milkfat fluid, yielding a robust taste. The resultingyogurt cream cheese product would be a welcome substitute for itsfaintly-tasting high-fat progenitor while simultaneously improving creamcheese production economics and protecting the environment. Since thebutterfat content of yogurt is typically between about 0% and about 3%by weight, and commonly less than about 0.5% by weight, the combinationof yogurt into a cream cheese product also would desirably yield a creamcheese having a lower overall butterfat content and relatively higherprotein content. Since cholesterol accompanies butterfat, thecholesterol content of this product would also be reduced.

SUMMARY OF THE INVENTION

In one embodiment according to the present invention, a process isprovided for making a yogurt cream cheese product comprising steps of:providing a milkfat fluid having an initial butterfat content level;pasteurizing the milkfat fluid to yield a cream cheese precursor;providing a yogurt, and combining the yogurt with the cream cheeseprecursor to yield a combined precursor; and homogenizing and acidifyingthe combined precursor; yielding a yogurt cream cheese product. Inanother embodiment according to the present invention, culture bacteriaare added to the milkfat fluid with agitation at an elevatedtemperature; and such bacteria are cultured in the milkfat fluid.

In another embodiment according to the present invention, a yogurt creamcheese product is provided, comprising between about 8% by weight andabout 35% by weight of total butterfat; in which the yogurt cream cheeseproduct comprises between about 10% by weight and about 40% by weight ofyogurt; and in which the yogurt cream cheese product has a viscositybetween about 1,000,000 centipoises and about 3,000,000 centipoises at atemperature of about 74° F.; and in which the yogurt cream cheeseproduct yields less than about 1% syneresis by weight after 15 hours atabout 74° F. to about 75° F.

A more complete understanding of the present invention, as well as otherfeatures and advantages of the present invention, will be apparent fromthe following detailed description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart of an exemplary process for making a yogurt creamcheese product according to the present invention;

FIG. 2 is a flow chart of an exemplary process for making yogurt forincorporation as an ingredient in the process according to FIG. 1; and

FIG. 3 is a flow chart of an exemplary process for making a whippedyogurt cream cheese product according to FIG. 1.

DETAILED DESCRIPTION

Referring to FIG. 1, a flow chart of an exemplary process 100 is shownfor making a yogurt cream cheese product according to the presentinvention. According to this process, a cream cheese precursor 105 isproduced in phase I generally indicated at 110. Subsequent steps definedin phase II generally indicated at 115 result in production of a yogurtcream cheese product 120.

Phase 1 of process 100 begins with provision of a milkfat fluid at step125. By milkfat is meant a composition comprising the fatty componentsof edible milk, for example, cow milk. Such fatty components, commonlyreferred to collectively as butterfat, can include, for example,triacylglycerols, diglycerides, monoacylglycerols, and other lipids. Byfluid is meant a liquefied composition comprising milkfat, which caneither be directly derived from milk, or reconstituted by hydrating adehydrated milk product. For example, the milkfat fluid can be cream.The milkfat fluid can be formed from a mixture of sources, including,for example, whole milk, cream, skim milk, and dry milk.

In one embodiment according to the present invention, the milkfat fluidhas a butterfat content between about 10% and about 50% by weight. Inanother embodiment according to the present invention, the milkfat fluidhas a butterfat content between about 33% and about 50% by weight,suitable for preparation of a yogurt cream cheese. In a furtherembodiment according to the present invention, the milkfat fluid has abutterfat content between about 39% and about 50% by weight. In anotherembodiment according to the present invention, the milkfat fluid has abutterfat content between about 40% and about 44% by weight. In yetanother embodiment according to the present invention, the milkfat fluidhas a butterfat content between about 17% and about 33% by weight,suitable for preparation of a yogurt neufchatel cheese. Although much ofthe ensuing discussion is addressed to embodiments according to thepresent invention for preparation of a yogurt cream cheese producthaving a butterfat content between about 33% and about 50% by weight, itwill be understood that the teachings according to the present inventionmay be applied to production of a yogurt neufchatel product having abutterfat content between about 17% and about 33% by weight, or toproduction of a yogurt light cream cheese product having a butterfatcontent between about 10% and about 17% by weight. The term yogurt creamcheese product as used herein therefore generally refers broadly to allof such products.

In an additional embodiment according to the present invention, themilkfat fluid has a water content between about 50% and about 60% byweight. For example, heavy cream may have a butterfat content of about37% by weight, a protein content of about 2% by weight, and a watercontent of about 58% by weight, with the balance made up by other milksolids. Butterfat is an essential ingredient in cheese, as the butterfatis coagulated together with proteins and other elements into a curd andfurther processed to produce the cheese.

In a further embodiment according to the present invention, the milkfatfluid is pasteurized at step 130. Prior to this step, the milkfat fluidtypically carries the wild bacteria load normally present in raw milkproducts. Pasteurization of the milkfat fluid is required at some pointin order to kill these undesirable bacteria, as well as other undesiredmicrobes to the extent reasonably feasible. Furthermore, if the milkfatfluid is to be subjected to culture bacteria in steps 140–145 or steps175–180 discussed below, pasteurization needs to be completed in advanceof those steps or the wild bacteria in the raw milkfat fluid willtypically digest and thereby spoil the product. Where a source ofpre-pasteurized milkfat fluid is employed, further pasteurization atthis point may be unnecessary.

Pasteurization causes irreversible heat-induced denaturation anddeactivation of bacteria. Effective pasteurization is a function of bothtime and temperature; pasteurization can be completed at highertemperatures in correspondingly shorter times. In one embodimentaccording to the present invention, pasteurization of the milkfat fluidin step 130 is carried out in a vat process at either a temperature ofabout 150° F. for about 30 minutes; or about 165° F. for about 15minutes. Other effective time and temperature treatment parameters areknown; and substitution of high surface area contact methods for the vatprocess can permit shorter effective treatment times. High temperatureshort time pasteurization for example, in which the milkfat fluid ispumped through an in-line tube within a temperature-controlled shell,can be used. Milkfat fluids having relatively high butterfat contentgenerally require more heat exposure than low butterfat fluids in orderto obtain effective pasteurization. Further background information onpasteurization of milk is provided in the Grade “A” Pasteurized MilkOrdinance published on May 15, 2002 by the U.S. Food & DrugAdministration, particularly at pages 62 and 63; the entirety of whichis hereby incorporated herein by reference.

Agitation is preferably provided and initiated prior to the heatingprocess during pasteurization to facilitate even heating throughout themilkfat fluid and to avoid localized overheating. The force applied bythe agitation should not be so strong as to substantially shear and thusdegrade the proteins and butterfat in the milkfat fluid. Desirably,pasteurization is carried out in a tank equipped with heating andagitation means. Any suitable vessel can be used, such as, for example,a Groen kettle.

According to one embodiment of the present invention, the temperature ofthe milkfat fluid is adjusted at step 135 to a bacteria culturetemperature. In another embodiment according to the present invention,the temperature of the milkfat fluid is adjusted to between about 65° F.and about 92° F. In an additional embodiment according to the presentinvention, the temperature of the milkfat fluid is adjusted to betweenabout 70° F. and about 85° F. In yet a further embodiment according tothe present invention, the temperature of the milkfat fluid is adjustedto about 82° F.

In one embodiment according to the present invention, culture bacteriaare added to the milkfat fluid at step 140, and then cultured at step145. The purpose of these steps is to generate robust culture-inducedflavor in the milkfat fluid. Milk contains lactose sugars that can bedigested by selected bacteria, producing lactic acid, glucose andgalactose as metabolites. Hence, the culture bacteria generally areselected from among those that can digest lactose. Preferably, a strainof mesophilic bacteria suitable for culturing cream cheese is used. Suchbacteria strains are typically chosen to produce diacetyl flavor.Bacteria strains may require ongoing rotational use, to preventbackground bacteriophage populations from becoming resistant to aparticular strain of bacteria, which can result in shutdown of theculture process and contamination of the product in production. Forexample, the culture bacteria may be selected from varying combinationsof strains, preferably rotated on an ongoing basis, of (1) lacticacid—producing Lactococcus lactis subspecies lactis or subspeciescremoris; and (2) diacetyl flavor—producing Lactococcus lactissubspecies diacetylactis or Leuconostoc strains. Suitable bacteriastrains are commercially available under the trade name pHage Control™from Chr. Hansen, Bøge Allé 10–12, DK-2970 Hørsholm, Denmark. Grades 604and 608 are particularly effective. These particular bacteria strainblends can be used continuously without rotation, provided that propersanitation is maintained. Further suitable bacteria strains arecommercially available under the trade names Flav Direct™ and DG™Cultures from Degussa BioActives, 620 Progress Avenue, P.O. Box 1609,Waukesha, Wis. 53187-1609.

Once a culture bacteria strain or strain mixture is selected, an amountis added to a given batch of milkfat fluid that is effective topropagate live cultures throughout the batch in a reasonable time at thechosen culture temperature. For example, 500 grams of bacteria may beeffective to inoculate up to 7,500 pounds of milkfat fluid using aninoculation proportion of about 0.015%. If desired, an inoculationproportion in the range between about 0.013% and about 0.026%, forexample, may be used. In general, greater proportional additions ofculture bacteria to a milkfat fluid batch will lead to somewhat reducedprocessing time, but at the expense of increased costs for the bacteria.

In one embodiment according to the present invention, the milkfat fluidis agitated following the addition of the culture bacteria, since theculture bacteria are typically added in a small proportion compared withthe milkfat fluid, and hence desirably are dispersed so that they canact throughout the milkfat fluid. Agitation can if desired begin priorto addition of the culture bacteria, and can if desired be continuedafter dispersion of the culture bacteria. The shear force applied by theagitation should be sufficient to disperse the culture bacteria in areasonable time, but not so strong as to substantially shear and thusdegrade the culture bacteria or the proteins and butterfat in themilkfat fluid. In one embodiment according to the present invention,moderate agitation of the milkfat fluid containing the culture bacteriais continued for between about 10 minutes and about 25 minutes. Inanother embodiment according to the present invention, moderateagitation is continued for about 15 minutes.

In step 145, the bacteria, if added at step 140, are cultured in themilkfat fluid. In one embodiment according to the present invention, themilkfat fluid is held at a suitable temperature long enough for culturesof the selected bacteria to begin development, resulting in a slightthickening of the milkfat fluid. The necessary duration of such bacteriaculturing depends on the level of bacteria activity, the selectedculture temperature, the initial bacteria concentration, and thecomposition of the milkfat fluid. The bacteria digest lactose sugars inthe milk. Higher culture temperatures and initial bacteriaconcentrations generally shorten the culture time needed. Thetemperature employed, however, must be within a range tolerable to thesurvival and growth of the selected culture bacteria. In one embodimentaccording to the present invention, the milkfat fluid is cultured withthe selected bacteria for between about 60 minutes and about 90 minutes.A bacteria culture step of such a limited duration generates a mildthickening of the milkfat fluid.

In one embodiment according to the present invention, the butterfatcontent of the milkfat fluid is standardized at step 150 to a desiredlevel. The butterfat content of the final yogurt cream cheese productcan then be projected based on the proportion of yogurt to be used, andits butterfat content. For example, cream cheese is defined to include aminimum butterfat content of 33% by weight. Given the variable nature ofraw milk, for example, standardization of the butterfat content in agiven batch of milkfat fluid may generally be desirable in furtheranceof process stability and production of a uniform product. According toone embodiment of the present invention, the butterfat content of themilkfat fluid is adjusted to between about 33% and about 50% by weight.According to another embodiment of the present invention, the butterfatcontent of the milkfat fluid is adjusted to between about 33% and about36% by weight. According to a further embodiment of the presentinvention, the butterfat content of the milkfat fluid is adjusted tobetween about 33% and about 34% by weight. According to yet anotherembodiment of the present invention, the butterfat content of themilkfat fluid is adjusted to about 34.5% by weight. According to yetanother embodiment of the present invention, the butterfat content ofthe milkfat fluid is adjusted to between about 17% and about 33% byweight. According to yet a further embodiment of the present invention,the butterfat content of the milkfat fluid is adjusted to between about10% and about 17% by weight.

In general, the texture and mouth feel of cream cheese improves withhigher butterfat content. Higher butterfat levels also provide bettertolerance of the milkfat fluid to processing steps, such as agitationshear that can degrade protein and butterfat molecules. However, higherbutterfat levels also lead to a correspondingly higher butterfat contentin the finished cream cheese, which is undesirable from a healthstandpoint. This standardization can alternatively be carried out priorto culturing the bacteria at step 145, but this practice generally isnot preferred.

The initial butterfat level present in a given batch of milkfat fluidcan be measured, for example, using a standard Babcock test. Forbackground, see Baldwin, R. J., “The Babcock Test,” MichiganAgricultural College, Extension Division, Bulletin No. 2, ExtensionSeries, March 1916, pp. 1–11; the entirety of which is hereinincorporated by reference. Where the initial butterfat level present ina given batch of milkfat fluid is too high, adjustment can beaccomplished by adding a nonfat material such as skim milk. Addition ofwater is generally ineffective since the water content of the curddirectly affects the product texture, and the feasibility of addingwater alone to adjust the butterfat level in the final product isaccordingly limited. In one embodiment according to the presentinvention, the butterfat content of a batch of milkfat fluid isdownwardly adjusted by addition of an appropriate amount of nonfat drymilk together with adequate water to rehydrate the nonfat dry milk,which has the advantage of not contributing excess water to the batch.In the event that the initial butterfat level present in a given batchof milkfat fluid needs to be upwardly adjusted, this can be accomplishedby addition of a material containing a higher concentration ofbutterfat, such as, for example, cream.

According to further embodiments of the present invention, the relativeconcentrations of butterfat, milkfat protein, and water are alladdressed. As explained above, the butterfat content of the final yogurtcream cheese product is selected as desired. For example, cream cheesegenerally needs to include at least about 33% by weight of butterfat.Regarding protein, higher concentrations are generally desirable fornutritional considerations. Water is a secondary ingredient that isnecessary to a reasonable degree to facilitate processing, as well as toprovide a desirable texture in the product. However, excessive waterwill not be retained in the curd and hence becomes a processinghindrance and expense, and a disposal issue. In one embodiment accordingto the present invention, the milkfat fluid comprises: about 34.5% toabout 50% butterfat, about 3% to about 7% milk protein, and about 59% toabout 42% water, with the balance constituted by other milk solids.

Referring to FIG. 1, a stabilizer is desirably added to the milkfatfluid at step 155. Stabilizers thicken the milkfat fluid by bindingwater, which may contribute to retention of whey in the milkfat fluidduring subsequent processing. Step 155 is preferably carried out aftercompletion of any bacteria culture in steps 135–145 and after completionof any standardization of the butterfat level at step 150; but can becarried out if desired at an earlier stage in phase I as generallyindicated at 110. Step 155 can also be carried out if desired at a laterstage in the process shown in FIG. 1. However, step 155 is preferablycompleted prior to homogenization step 185 discussed further below, sothat any lumpy texture in the product resulting from stabilizer additionis corrected during homogenization.

The stabilizer may be selected from, for example, gums, salts,emulsifiers, and their mixtures. Suitable gums include, for example,locust bean gum, xanthan gum, guar gum, gum arabic, and carageenan.Suitable salts include, for example, sodium chloride and potassiumchloride. Suitable emulsifiers include, for example, sodium citrate,potassium citrate, mono-, di-, and tri-sodium phosphate, sodium aluminumphosphate, sodium tripolyphosphate, sodium hexametaphosphate,dipotassium phosphate, and sodium acid pyrophosphate. In one embodimentaccording to the present invention, the stabilizer is K6B493, a milled,dry product that is commercially available from CP Kelco US, Inc., 1313North Market Street, Wilmington, Del. 19894-0001. Gum arabic iscommercially available from TIC Gums Inc., Belcamp, Md. Gum-basedstabilizers typically contain sodium, which should be taken into accountin order to avoid excessive sodium concentrations in the final yogurtcream cheese product. For this reason, use of salts as stabilizers isalso not preferred. However, the incorporation of a significantproportion of yogurt into the final product reduces the proportionalsodium content, as yogurt typically has a low sodium concentration.

Preferably, an amount of a stabilizer effective to cause a moderatethickening of the milkfat fluid is added. For example, a stabilizer maybe added in an amount constituting between about 0.2% by weight to about0.5% by weight of the yogurt cream cheese product. In anotherembodiment, a stabilizer may be added in an amount constituting about0.45% by weight of the yogurt cream cheese product. As the butterfatcontent of the chosen milkfat fluid is reduced, the proportion ofstabilizer used preferably is increased.

In one embodiment according to the present invention, bacteria culturestep 145 is terminated by initiating pasteurization at step 160 beforesubstantial thickening of the milkfat fluid occurs. Limiting bacteriaculture step 145 to a mild thickening of the milkfat fluid according tothis embodiment of the present invention is a fundamental and majordeparture from normal production of cream cheese, in which bacteriaculture is typically permitted to run its course until the pH of themilkfat fluid is reduced to a range between about 5.0 and about 4.1. Inthe case of such a mild bacteria culture step, there may be very littlechange in the pH of the milkfat fluid. In one embodiment according tothe present invention, the temperature of the milkfat fluid is graduallyraised during processing in phase I, so that the temperature continuesto rise after completion of bacteria culture in step 145. Hence,pasteurization is initiated in due course when the milkfat fluid reachesan effective pasteurization temperature.

In an alternative embodiment according to the present invention, thebacteria added to the milkfat fluid at step 140 may be cultured for asufficient time to partially or substantially digest the milkfat fluid,as limited by the attendant pH reduction. Lactic acid is formed as abyproduct of metabolism of lactose by the bacteria in step 145. Hence,the measured pH of the milkfat fluid, which gradually decreases withlactic acid buildup, is an indication of the progress of the bacteriaculture. If it is desired, for example, to substantially digest themilkfat fluid, then the bacteria culture step 145 may be continued untilthe pH of the milkfat fluid is within a range of about 5.0 to about 4.1,or within a range of about 4.6 to about 4.4, at either of which pointsthe bacteria activity becomes substantially dormant.

In one embodiment according to the present invention, the cream cheeseprecursor is then cooled at step 165 to a bacteria culture temperature.Once the pasteurization of the milkfat fluid is completed, it isgenerally desirable to promptly lower the temperature of the creamcheese precursor to a more moderate level in order to reduce ongoingheat damage to the butterfat and milk proteins. In addition, it may bedesired to further culture bacteria in the cream cheese precursor atsteps 175–180 of phase II, as will be discussed further below. The hightemperatures necessary for pasteurization cannot then be maintained,because they will kill the culture bacteria. Preferably, the creamcheese precursor is cooled to a temperature that will facilitatereaching an appropriate temperature for carrying out phase II. In oneembodiment according to the present invention, the cream cheeseprecursor is cooled to a temperature between about 90° F. and about 125°F. In another embodiment according to the present invention, the creamcheese precursor is cooled to a temperature between about 110° F. andabout 120° F. If, alternatively, the cream cheese precursor 105 will bestored prior to further processing, then it is preferably cooled to arefrigeration temperature such as, for example, a temperature betweenabout 34° F. and about 38° F.

The resulting cream cheese precursor 105 is then ready for furtherprocessing according to phase II generally indicated at 115 in FIG. 1.This cream cheese precursor is a uniform, fluid material containing thebutterfat and whey from the milkfat fluid. The cream cheese precursor issubstantially free of bacterial activity due to its pasteurization,unless the culture bacteria have been added following pasteurization,for example so that they can be permitted to digest the milkfat fluidthrough to a pH of between about 5.0 and about 4.1, or through to a pHof between about 4.6 and about 4.4. The preparation of the cream cheeseprecursor does not require and preferably does not includehomogenization or acidification at any point in phase I generallyindicated at 110, which are steps normally included in preparation ofcream cheese, although these steps can be undertaken if desired. Infurther embodiments according to the present invention the cream cheeseprecursor is not subjected to a full bacteria culture that would takethe product pH and texture to its normal completion in production ofcream cheese. Acidification at this point, for example, would cause thecurd and whey to separate, defeating the goal of including the whey inthe final yogurt cream cheese product. Homogenization, for example, iswholly unnecessary at this stage of the production of the yogurt creamcheese product. Homogenization at this point would subject the creamcheese precursor to unnecessary processing that would needlesslyincrease the processing time and costs, while not substantiallycontributing to the quality of the final yogurt cream cheese product.

The cream cheese precursor produced according to the process of thepresent invention is not cream cheese. Substitution of cream cheese forthe cream cheese precursor as an ingredient in step 170 to be discussedbelow defeats the desirable goal of providing a cream cheese producthaving retained whey, because whey is separated from the curd inconventional cream cheese production. Moreover, cream cheese and yogurtcannot be directly combined in mutually substantial proportions to yielda homogenous single-phase product.

Although the process according to the present invention does not produceconventional cream cheese, nevertheless conventional cream cheese can ifdesired be an ingredient in the yogurt cream cheese product. Forexample, conventional cream cheese can, if desired, be added to thecream cheese precursor in any desired proportion. As the proportion ofconventional cream cheese in the final yogurt cream cheese productincreases, the benefits of the teachings according to the presentinvention are achieved to a correspondingly reduced degree.

Referring to FIG. 1, the cream cheese precursor and a source of yogurtare then combined at step 170 to produce a combined precursor. Ingeneral, any yogurt may be used. Yogurt is broadly defined as a milkfatfluid that is cultured by at least one bacteria strain that is suitablefor production of yogurt. In one embodiment according to the presentinvention, the yogurt comprises: about 0% to about 3% butterfat, about3% to about 6% milk protein, and about 76% to about 88% water. Inanother embodiment according to the present invention, the yogurtcomprises: about 0.5% to about 3.25% butterfat, about 3.47% to about5.25% milk protein, and about 76% to about 88% water. In yet a furtherembodiment according to the present invention, the yogurt comprises:about 0.5% to about 2.0% butterfat, about 5% milk protein, and about 85%water. In still another embodiment according to the present invention,the yogurt comprises about 0.16% butterfat, about 5.12% milk protein,and about 76% water. In general, any of the foregoing yogurts will havea total solids content of at least about 8% by weight.

In one embodiment according to the present invention, suitable yogurt isprepared according to the exemplary process 200 shown in FIG. 2.Referring to FIG. 2, milk is provided at step 210. The milk employed toproduce the yogurt can be, for example, whole milk, reduced fat milk, orskim milk. Butterfat present in the milk facilitates processing becausebutterfat contributes to the feasibility of thickening the final productto a desirable consistency. However, butterfat present in the milk usedin producing the yogurt also results in a higher butterfat concentrationin the final yogurt cream cheese product. In one embodiment according tothe present invention, the milk employed to produce the yogurtaccordingly is skim milk. In another embodiment according to the presentinvention, the butterfat content of the milk is less than 1% by weight.In any case, the selected milk can be directly sourced from liquid milksuch as cow milk, or it can be reconstituted from dry milk.

In a further embodiment according to the present invention, the solidslevel of the milk to be used in preparing the yogurt is standardized tobetween about 18% and about 22% by weight. In another embodimentaccording to the present invention, the solids level of the milk isstandardized to about 20% by weight. Alternatively, the solids level ofthe milk can be standardized to between about 10% and about 12% byweight, as is employed in conventional preparation of yogurt. However,such a relatively low solids level can hinder production of a finalyogurt cream cheese product having a desirably thick texture. The solidscontent of the milk provided at step 210 can be increased if desired byany process suitable to yield a condensed milk. Condensation processesthat do not involve heating the milk, such as ultrafiltration, arepreferred in order to reduce processing damage of the milk.

At step 220, the milk is pasteurized. Pasteurization should generally becarried out as earlier discussed, for example, at a temperature of atleast about 165° F. for at least about 15 minutes. In one embodimentaccording to the present invention, pasteurization of the milk iscarried out at a temperature of about 162° F. to about 165° F. for about30 minutes to about 15 minutes. Agitation should be provided tofacilitate even heating of the milk and to avoid localized overheating.

At step 230, the milk is then cooled to a bacteria culture temperature.Once the pasteurization of the milk is completed, it is generallydesirable to promptly lower the temperature of the milk to a moremoderate level in order to reduce ongoing heat damage. In addition,bacteria will be cultured in the milk at steps 240–250, as will bediscussed further below. As pointed out above, the high temperaturesnecessary for pasteurization cannot persist when the culture bacteriaare added at step 240. In one embodiment according to the presentinvention, the milk is cooled at step 230 to a temperature between about90° F. and about 115° F. In another embodiment according to the presentinvention, the milk is cooled at step 230 to a temperature between about106° F. and about 110° F. In yet a further embodiment according to thepresent invention, the milk is cooled at step 230 to a temperature ofabout 108° F.

At step 240, culture bacteria are added to the milk. Since yogurt is thedesired product of the process in FIG. 2, bacteria strains that aresuitable for production of yogurt are used. For example, Lactobacillusdelbrueckii subspecies bulgaricus, Streptococcus thermophilus,Lactobacillus acidophilus, Bifidobacterium, and Lactobacillus paracaseisubspecies casei can be used. If available, other lactic acid—producingbacteria strains suitable for making yogurt can be used. Suitable yogurtculture bacteria strains are commercially available under the trade nameYo-Fast® from Chr. Hansen, Bøge Allé 10–12, DK-2970 Hørsholm, Denmark.In one embodiment according to the present invention, F-DVS YoFast®-10is used, which contains blended strains of Streptococcus thermophilus,Lactobacillus delbrueckii subspecies bulgaricus, Lactobacillusacidophilus, Bifidobacterium, and Lactobacillus paracasei subspeciescasei. In another embodiment according to the present invention, DVSYoFast®-2211 is used. Further suitable bacteria strains are commerciallyavailable under the trade names Ultra-Gro® and Sbifidus® from DegussaBioActives, 620 Progress Avenue, P.O. Box 1609, Waukesha, Wis.53187-1609.

Once a culture bacteria strain is selected, an amount is added to themilk that is effective to propagate live cultures throughout a givenbatch of milk in a reasonable time at the chosen culture temperature. Ingeneral, greater proportional additions of culture bacteria to a milkbatch will reduce processing time, but at the expense of increased costsfor the bacteria.

In one embodiment according to the present invention, the milk isagitated following the addition of the culture bacteria, since theculture bacteria are typically added in a small proportion compared withthe milk, and desirably are dispersed so that they can act throughoutthe milk. Agitation can if desired begin prior to addition of theculture bacteria, and can if desired be continued after dispersion ofthe culture bacteria. The shear force applied by the agitation should besufficient to disperse the culture bacteria in a reasonable time, butnot so strong as to shear and thus degrade the culture bacteria or theproteins and butterfat in the milk. In one embodiment according to thepresent invention, moderate agitation of the milk containing the culturebacteria is continued for between about 10 minutes and about 25 minutes.In another embodiment according to the present invention, moderateagitation is continued for about 15 minutes.

In step 250, the bacteria added at step 240 are cultured in the milk.The milk is held at a suitable temperature for cultures of the selectedbacteria to develop for a sufficient time so that there is visible curdformation throughout the milk, resulting in a substantial thickening. Inone embodiment according to the present invention, the milk is held at atemperature between about 106° F. and about 110° F. In anotherembodiment according to the present invention, the milk is held at atemperature of about 108° F. The necessary duration of the bacteriaculturing depends on the level of bacteria activity, the selectedculture temperature, the initial bacteria concentration, and thecomposition of the milk. In one embodiment according to the presentinvention, the milk is cultured with the selected bacteria for betweenabout 4 hours and about 6 hours. In another embodiment according to thepresent invention, the milk is cultured with the selected bacteria at atemperature of about 108° F. for about 6 hours.

Lactic acid is formed as a byproduct of metabolism of lactose by thebacteria in step 250. Hence, the measured pH of the milk, whichgradually decreases with lactic acid buildup, is an indication of theprogress of the bacteria culture. Further, when the pH of the milkreaches about 4.4, the level of bacterial activity begins to markedlydecrease. In one embodiment according to the present invention, thebacteria culture step 250 is continued until the pH of the milk iswithin a range of about 5.0 to about 4.1. In another embodimentaccording to the present invention, the bacteria culture step 250 iscontinued until the pH of the milk is within a range of about 4.6 toabout 4.4; and more preferably about 4.5.

When the bacteria culture step 250 is complete, the resulting product isyogurt 260 containing live bacteria cultures. Preferably, the yogurt hasa uniform consistency with a solids content of at least about 8%.

Returning to FIG. 1, phase II begins with combining the cream cheeseprecursor and a yogurt source together at step 170 to yield a combinedprecursor. Bacteria may be cultured in the combined precursor at step180, to be discussed below. Accordingly, yogurt and the cream cheeseprecursor desirably are simultaneously prepared so that phase II of FIG.1 as generally indicated at 115 can then immediately be carried out. Inthis manner, the active yogurt 260 is already at a suitable temperaturefor any further bacteria culture to be carried out at step 180; and thecream cheese precursor 105 can be cooled at step 165 to that samesuitable temperature or to another compatible temperature.Alternatively, if the yogurt 260 is prepared in advance of undertakingphase II of FIG. 1, then the yogurt should be cooled in the meantime toa refrigeration temperature such as, for example, between about 34° F.and about 38° F., to retard unwanted continuation of bacterial activity,and then reheated.

In one embodiment according to the present invention, the cream cheeseprecursor and yogurt are combined in step 170 of FIG. 1 at selectedtemperatures, in selected proportions, and in a selected manner.

Assuming that the above-discussed preparations of the cream cheeseprecursor and yogurt have been simultaneously completed, the respectivetemperatures of these ingredients are preferably controlled withattention both to preserving live culture bacteria in the yogurt and tominimizing further heating and cooling operations. Desirably, the creamcheese precursor and yogurt are both maintained at a temperaturesuitable for bacteria culture. If either ingredient to be so used iseither too hot or too cold, its temperature can be adjusted. In oneembodiment according to the present invention, the temperatures of boththe cream cheese precursor and the yogurt are adjusted to between about90° F. and about 120° F. In another embodiment according to the presentinvention, the temperatures of both the cream cheese precursor and theyogurt are adjusted to between about 110° F. and about 120° F.

The proportions of cream cheese precursor and yogurt to be combined atstep 170 are a matter of discretion. However, the cream cheese precursortypically contains a relatively higher concentration of butterfat, andthe yogurt typically contains a relatively lower concentration ofbutterfat, cholesterol and sodium, and a relatively higher concentrationof milk protein. Further, a substantial proportional addition of yogurtto the cream cheese precursor contributes the robust flavor, reducedcholesterol, and healthful active bacteria cultures of yogurt to theoverall product. Hence, according to one embodiment of the presentinvention a sufficient proportion of yogurt is used relative to a givenbatch of cream cheese precursor, to yield a desired substantialimprovement in the flavor and substantial influence of the beneficialconstituents in the yogurt on their mixture relative to that in thecream cheese precursor.

According to another embodiment of the present invention, the mixture ofcream cheese precursor and yogurt is controlled to comprise betweenabout 10% and about 40% by weight of yogurt. In an additional embodimentaccording to the present invention, the mixture of cream cheeseprecursor and yogurt is controlled to comprise between about 14% andabout 30% by weight of yogurt. According to a further embodiment of thepresent invention, the mixture of cream cheese precursor and yogurt iscontrolled to comprise about 14% and about 22% by weight of yogurt.According to an additional embodiment of the present invention, themixture of cream cheese precursor and yogurt is controlled to compriseabout 20% by weight of yogurt. Where flavorings are to be added to thecream cheese product, slightly lower proportions of yogurt generally arepreferred, for example about 14% to about 18% by weight of yogurt, andmore preferably about 16% by weight of yogurt.

The cream cheese precursor and the yogurt can generally be combinedtogether in any suitable manner. Where the relative proportion of yogurtis small compared to the proportion of cream cheese precursor, it isgenerally easier to combine the minor yogurt ingredient into the majorcream cheese precursor ingredient. If the cream cheese precursor is at atemperature that is above the range of temperatures tolerable to theactive culture bacteria in the yogurt, then preferably the yogurt isprovided at a temperature substantially below the maximum temperaturetolerable to the yogurt and substantially below the temperature of thecream cheese precursor, so that the cream cheese precursor is cooled oncontact with the yogurt. In one embodiment according to the presentinvention, the yogurt is chilled to a temperature between about 34° F.and 36° F. In general, the cream cheese precursor and the yogurt arecombined with moderate agitation for a time sufficient to thoroughly mixthem together. Care should again be taken to minimize shearing of milkproteins, butterfat, and the live culture bacteria. In one embodimentaccording to the present invention, moderate agitation of the combinedingredients is continued for between about 15 minutes and about 20minutes.

At step 175, live culture bacteria may desirably be added to thecombined precursor. If the yogurt employed at step 170 contains livebacteria cultures, this step may be completely unnecessary.Alternatively, if the selected yogurt does not contain live bacteriacultures, then such cultures may, if desired, be added at step 175. Inanother embodiment according to the present invention in which the creamcheese precursor was not subjected to culture of bacteria at step 145,culture by yogurt bacteria may be carried out at this point. In general,culture bacteria can be so added if desired following the guidelinesdiscussed above regarding step 240 of FIG. 2, preferably with agitation.Live yogurt bacteria cultures themselves provide well-known healthbenefits to the consumer, and accordingly are preferably included in thefinal yogurt cream cheese product. Although the combined precursor canalso or alternatively be cultured by cream cheese culture bacteria suchas may be employed at step 140, such cream cheese bacteria do nottypically provide the health benefits that are provided to the consumerby live yogurt bacteria.

In one embodiment according to the present invention, yogurt bacteriaare then cultured in the combined precursor at step 180. The combinedprecursor is held at a suitable temperature for cultures of the selectedbacteria to develop for a sufficient time so that there is visible curdformation throughout the combined precursor, resulting in a substantialthickening and a significant reduction in the pH. In one embodimentaccording to the present invention, the combined precursor is held at atemperature between about 110° F. and about 120° F. In anotherembodiment according to the present invention, the combined precursor isheld at a temperature of about 108° F. In an additional embodimentaccording to the present invention, the combined precursor is culturedwith the selected bacteria for between about 4 hours and about 6 hours.In another embodiment according to the present invention, the combinedprecursor is cultured with the selected bacteria at a temperature ofabout 108° F. for about 6 hours. In yet a further embodiment accordingto the present invention, the bacteria culture step 180 is continueduntil the pH of the combined precursor is within a range of about 5.0 toabout 4.1, more preferably about 4.6 to about 4.4, and still morepreferably about 4.5.

At step 185, the combined precursor is homogenized by subjecting it toan elevated pressure at an elevated temperature for a suitable period oftime. Application of such an elevated pressure breaks down the butterfatglobules in the combined precursor, resulting in substantially increaseduniformity. In general, the elevated pressure can be applied to thecombined precursor by any suitable means, such as, for example,hydraulic or mechanical force. In one embodiment according to thepresent invention, the combined precursor is compressed to the selectedpressure and then passed through an orifice to quickly reduce suchpressure. In another embodiment according to the present invention,homogenization is carried out at a controlled temperature between about120° F. and about 125° F. Although higher temperatures can be used,desirably a temperature is chosen that will not kill the live culturebacteria in the product. Homogenization can be carried out, for example,in a Gaulin homogenizer. Preferably, homogenization is carried out aftercompletion of any desired bacteria culture at step 180, but the order ofsuch steps can be inverted.

In one embodiment according to the present invention, the homogenizationpressure is between about 2,000 pounds per square inch (PSI) to about4,000 PSI. In another embodiment according to the present invention, thehomogenization pressure is between about 2,500 PSI to about 3,200 PSI.As the applied pressure increases, the resulting viscosity of the finalyogurt cream cheese product accordingly increases. Hence, the pressureto be applied is preferably chosen to yield a final product of thedesired consistency.

At step 190, the combined precursor is acidified to a pH suitable toretard activity of the culture bacteria, and to coagulate the combinedprecursor to yield the yogurt cream cheese product 120. Preferably,acidification at step 190 is carried out after homogenization at step185 is completed. Acidification causes substantial thickening of thecombined precursor, and may hinder homogenization if previously carriedout. However, the order of homogenization step 185 and acidificationstep 190 can be inverted so that acidification is carried out first, ifdesired; or these steps can be concurrently carried out. In oneembodiment according to the present invention, the pH is adjusted towithin a range of about 5.0 to about 4.1, more preferably about 4.6 toabout 4.4, and still more preferably about 4.5. In another embodiment inaccordance with the present invention, the pH is adjusted by adding anappropriate amount of an edible acid to the combined precursor.

Edible acids include, for example, lactic acid, phosphoric acid, aceticacid, citric acid, and mixtures. For example, a suitable aqueous mixtureof edible acids having a pH between about 0.08 and about 1.4 isavailable under the trade name Stabilac® 12 Natural from theFantasy-BlankeBaer Corporation, 1572 Larkin Williams Rd., Fenton, Mo.63026-3009. In another embodiment according to the present invention,the edible acid is lactic acid, being the metabolite naturally producedby the lactose-consuming bacteria that are used in producing the yogurtand the cream cheese precursor.

Since the thickness of the resulting product increases as the pH isreduced, edible acid addition can be used to control the thickness ofthe final yogurt cream cheese product. Furthermore, live culturebacteria in the final product cannot survive at a pH substantially below4.4, hence acidification substantially slows down their furtherpropagation in the product, extending its shelf life. However, theyogurt bacteria are not killed by this acidification process, and thuscan still provide the health benefits of active yogurt cultures to theconsumer. The edible acid present in the final yogurt cream cheeseproduct also serves to provide a good-tasting bite to the flavor.

In an alternative embodiment, a coagulating enzyme can be substitutedfor or used in conjunction with acidification. Enzymatic coagulationtypically causes the whey to separate from the curd, and accordinglyenzymatic coagulation generally is not preferred. However, it may befeasible to reincorporate the whey into the combined precursor so longas the enzyme coagulation is carried out before homogenization.Enzymatic coagulation also typically takes a long time, 12 hours forexample, which is another disadvantage of its use in the process. Ingeneral, any suitable coagulating enzyme of animal-, plant-, microbial,or other origin can be used. In one embodiment, the coagulant enzyme ischymosin, also referred to as rennin, which is the active component ofrennet. Rennet is purified from calf stomachs. Chymosin breaks down amilk protein, casein, to paracasein. Paracasein then combines withcalcium to form calcium paracaseinate, which precipitates and startsformation of a solid mass. Milkfat and water then become incorporatedinto the mass, forming curds. One part rennin can coagulate about 10,000to about 15,000 parts milkfat fluid. Alternatively, pepsin, which ispurified from the stomachs of grown calves, heifers, or pigs, can beused.

The temperature of the yogurt cream cheese product is preferably reducedto a suitable refrigeration temperature, such as, for example, about 34°F. to about 38° F. If desired, a suitable preservative can be added tothe yogurt cream cheese product to retard yeast and mold growth. Forexample, potassium sorbate, sodium benzoate, sorbic acid, ascorbic acidor nisin can be added, preferably before acidification to facilitatetheir dispersion in minor proportion throughout the yogurt cream cheeseproduct. Nisin, for example, is a protein made by Lactococcus lactis.Further, if desired, flavorings, condiments and the like can be added.Adjuvants that are vulnerable to attack by the live bacteria arepreferably added after reducing the temperature of the yogurt creamcheese product, and may need to be made resistant to such bacteria.

The yogurt cream cheese product made according to the process of thepresent invention generally has the appearance, consistency, and textureof cream cheese. In addition, this product has the robust, desirableflavor of yogurt. Further, the product includes retained whey from themilkfat fluid, which dramatically amplifies the flavor of the product,giving it a greatly superior and robust taste. Retention of the whey inthis manner adds natural flavor without subjecting the product to largeproportions of adulterating additives or heavy extra processing steps,and eliminates the pollution and economic loss resulting from wheyseparation in conventional cream cheese production. In addition, theyogurt cream cheese product has reduced cholesterol and sodium.

Cream cheese by definition contains at least 33% butterfat. In oneembodiment in accordance with the present invention, the yogurt creamcheese product accordingly comprises between about 33% and about 40%butterfat. Neufchatel cheese by definition contains between about 17%and about 33% butterfat. In one embodiment in accordance with thepresent invention, the yogurt cream cheese product accordingly comprisesbetween about 17% and about 33% butterfat. Low-fat cream cheese bydefinition contains between about 10% and about 17% butterfat. In oneembodiment in accordance with the present invention, the yogurt creamcheese product accordingly comprises between about 10% and about 17%butterfat.

Addition of significant proportions of yogurt tends to somewhat reducethe butterfat content of the overall yogurt cream cheese product. Thus,in one embodiment according to the present invention, the yogurt creamcheese product comprises between about 8% by weight and about 35% byweight of butterfat. In another embodiment according to the presentinvention, the yogurt cream cheese product comprises between about 10%by weight and about 26% by weight of butterfat. In yet anotherembodiment according to the present invention, the yogurt cream cheeseproduct comprises between about 23% by weight and about 26% by weight ofbutterfat. In yet a further embodiment according to the presentinvention, the yogurt cream cheese product comprises between about 25%by weight and about 26% by weight of butterfat. In yet a furtherembodiment according to the present invention, the yogurt cream cheeseproduct further comprises 2% by weight and about 14% by weight of milkprotein, more preferably between about 3% by weight and about 8% byweight of milk protein, and still more preferably between about 4% byweight and about 5% by weight of milk protein. In another embodimentaccording to the present invention, the yogurt cream cheese productcomprises between about 0.05% and about 0.09% by weight of cholesterol;between about 0.2% by weight and 0.4% by weight of sodium; and betweenabout 58% by weight and 63% by weight of water.

Various highly processed dairy derivatives have the potential for use inmodifying the flavor and texture of cream cheese products. Thesederivatives include, for example, milk protein concentrate, whole milkprotein, whey protein concentrate, casein, Baker's cheese, yogurt powderand dry cottage cheese curd. Milk protein concentrate, for example, isproduced by ultrafiltration of milk. Such materials could be added tothe yogurt cream cheese product made in accordance with the presentinvention, or introduced during preparation of the product. However,their use is not preferred, and can by practice according to the presentinvention be minimized. Furthermore, addition of such agents generallyis a poor substitute for the retention of whey from the milkfat fluidand the incorporation of yogurt, both such desirable results being asachieved in accordance with the present invention. In one embodimentaccording to the present invention, at least about 40% of the milkprotein in the yogurt cream cheese product is derived from the milkfatfluid and yogurt. In another embodiment according to the presentinvention, at least about 50% of the milk protein in the yogurt creamcheese product, and potentially in excess of 60% of the milk protein inthe yogurt cream cheese product, is derived from the milkfat fluid andyogurt.

Syneresis leads to an unattractive and wasteful phase separation betweencurds and whey when milk is directly coagulated. In one embodimentaccording to the present invention, the yogurt cream cheese productexhibits substantially no syneresis, or less than about 1% syneresis byweight, after 15 hours at about 74° F. to about 75° F.

The texture and consistency of the yogurt cream cheese product made inaccordance with one embodiment of the present invention is the same asthat of ordinary cream cheese. For example, the yogurt cream cheeseproduct may have a viscosity between about 1,000,000 centipoises andabout 3,000,000 centipoises at a temperature of about 74° F. In anotherembodiment according to the present invention, the yogurt cream cheeseproduct has a viscosity between about 1,000,000 centipoises and about2,000,000 centipoises at a temperature of about 74° F. Viscosity isconventionally measured, using, for example, a Brookfield viscometer.

In yet a further embodiment according to the present invention, theconsistency of the yogurt cream cheese product can be modified to yielda whipped, more easily spreadable product. Referring to FIG. 3, anexemplary process 300 for carrying out a whipping operation is shown.The process begins with providing a yogurt cream cheese product at step310, in accordance with the above teachings. At step 320, the yogurtcream cheese product is agitated in the presence of an inert gas at anelevated pressure. For example, the yogurt cream cheese product can bepassed through a confined space having agitation means, while beingsimultaneously subjected to an inert gas at an elevated pressure.

In one embodiment according to the present invention, the gas isprovided at an initial pressure between about 150 PSI and about 240 PSI.In another embodiment according to the present invention, the inert gasis provided at an initial pressure between about 220 PSI and about 240PSI. In yet a further embodiment according to the present invention, thepressure of the inert gas is controlled throughout the agitation meansin order to expose the yogurt cream cheese product to a desired pressurefor a defined time as it travels through the agitation means. In anotherembodiment according to the present invention, the inert gas is injectedinto the agitation means at a chosen initial pressure, which is thenpermitted to dissipate in the region of the agitation means. In oneembodiment according to the present invention, the yogurt cream cheeseproduct is exposed to a desired pressure for between about 3 seconds andabout 6 seconds. In an additional embodiment according to the presentinvention, the yogurt cream cheese product is exposed to a desiredpressure for between about 4 seconds and about 5 seconds. Although anyinert gas can be used, nitrogen is the typical and most practicalchoice.

Desirably, the temperature of the yogurt cream cheese product is reducedto a whipping temperature as indicated at step 340, and so maintained orfurther modified during step 320. For example, a scraped surface heatexchanger, such as a Waukesha Cherry-Burrell Thermutator® or Votator®,can be used to provide the needed agitation while simultaneouslycontrolling the temperature. In one embodiment according to the presentinvention, the yogurt cream cheese product is cooled to a whippingtemperature between about 70° F. and about 90° F., more preferably about80° F., at step 340. A temperature between about 60° F. and about 70°F., more preferably about 68° F., is employed within the agitation meansat step 320. In another embodiment according to the present invention,the yogurt cream cheese product is cooled to a whipping temperature ofabout 80° F. at step 340, and then a temperature of about 68° F. isemployed within the agitation means at step 320. Using highertemperatures counteracts the effect of the pressurized gas in causingthe yogurt cream cheese product to expand into whipped form andaccordingly is to be avoided.

The agitation within the scraped surface heat exchanger may becontrolled to a desired level in order to maintain the yogurt creamcheese product within the exchanger for an adequate time for thepressurized inert gas to act on the product. The normal operating speedof the agitator in a Waukesha Cherry-Burrell Thermutator® or Votator®may need to be reduced, for example to between about 800 and 1,000revolutions per minute, in order to avoid excessive shear. In order tofacilitate further reduction of the temperature of the yogurt creamcheese product in the course of passage through the scraped surface heatexchanger, such exchanger is equipped to withdraw heat from the product,which is then dissipated in a suitable manner. In one embodimentaccording to the present invention, two scraped surface heat exchangersare operated in series so that the yogurt cream cheese product issuccessively passed through both exchangers, which jointly cool andapply pressurized inert gas to the yogurt cream cheese product.

The resulting product indicated at 330 is a whipped yogurt cream cheeseproduct. The texture and consistency of the yogurt cream cheese productmade in accordance with one embodiment of the present invention is thesame as that of ordinary whipped cream cheese. For example, the whippedyogurt cream cheese product may have a viscosity between about 500,000centipoises and about 1,500,000 centipoises at a temperature of about74° F.

Where it is desired to add solid adjuvants such as fruits, vegetables ornuts to the yogurt cream cheese product, they are preferably added afterthe whipping process is completed.

EXAMPLE 1

A batch of 1,500 pounds of pre-pasteurized heavy cream having abutterfat content of 44% was pumped into a kettle equipped with heatingand agitation means. The cream was heated with agitation to 85° F.,whereupon 500 milligrams of pHage Control™ 604 cream cheese culturebacteria were added to the cream with agitation for 15 minutes. Thecream was then maintained at 85° F. for 75 minutes. The butterfatcontent of the cream was then adjusted to 33% by weight by the additionwith agitation of 195.8 pounds of nonfat dry milk and 180 pounds ofwater. After 15 minutes of agitation, 9.01 pounds of K6B493 stabilizerwas added to the cream with agitation to thicken the mixture. The creamwas then pasteurized by heating it with agitation to 165° F. and holdingat that temperature for 15 minutes. The temperature of the resultingcream cheese precursor was adjusted to 130° F. Approximately 29% byweight of the protein content in this cream cheese precursor was derivedfrom the cream; the balance being derived from the nonfat dry milk andstabilizer.

Meanwhile, yogurt was separately and simultaneously prepared. A batch of312 pounds of condensed nonfat milk having a solids content of 33% byweight was provided. The solids content was adjusted to 20% by weight,by addition of 187 pounds of water. The condensed milk was thenpasteurized by heating it with agitation to 165° F. and holding at thattemperature for 15 minutes. The temperature of the condensed milk wasthen adjusted to 108° F., whereupon 250 milligrams of F-DVS YoFast®-10yogurt culture bacteria were added to the condensed milk with agitationfor 15 minutes. The condensed milk was then maintained at 108° F. for 6hours. The resulting yogurt was then ready for combination with thecream cheese precursor. Next, 470 pounds of the prepared yogurt wasmixed into 1,880 pounds of the cream cheese precursor with agitation.The mixture was cooled to a temperature of 125° F., and then homogenizedby subjecting the mixture to a pressure of about 3,000 PSI at atemperature of 125° F. for about 5 seconds. The homogenized mixture wasthen acidified to a pH of about 4.5 by addition of 25 pounds ofStabilac® 12 Natural acid.

The resulting yogurt cream cheese product comprised about 25.9% byweight of butterfat; about 4.54% by weight of milk protein; about0.0813% by weight of cholesterol; about 0.211% by weight of sodium;about 58.3% by weight of water; and about 41.7% by weight of solids.Concerning the protein content of this final product, approximately: 57%was derived from the nonfat dry milk together with the stabilizer; 23%was derived from the cream; and 20% was derived from the yogurt. Theyogurt cream cheese product had a viscosity of about 1,336,000centipoises at a temperature of about 74° F., and yielded substantiallyno syneresis after 15 hours at about 74° F. to about 75° F.

EXAMPLE 2

A batch of 1,335 pounds of pre-pasteurized heavy cream having abutterfat content of 44% is pumped into a kettle equipped with heatingand agitation means. The cream is heated with agitation to 85° F.,whereupon 500 milligrams of pHage Control™ 604 cream cheese culturebacteria are added to the cream with agitation for 15 minutes. The creamis then maintained at 85° F. for 75 minutes. The butterfat content ofthe cream is then adjusted to 23.5% by weight by the addition withagitation of 244 pounds of nonfat dry milk and 765 pounds of water.After 15 minutes of agitation, 11.25 pounds of K6B493 stabilizer isadded to the cream with agitation to thicken the mixture. The cream isthen pasteurized by heating it with agitation to 165° F. and holding atthat temperature for 15 minutes. The temperature of the resulting creamcheese precursor is adjusted to 130° F. Approximately 54% by weight ofthe protein content in this cream cheese precursor is derived from thecream; the balance being derived from the nonfat dry milk andstabilizer.

Yogurt is separately and simultaneously prepared in the same manner asdescribed in Example 1. Next, 500 pounds of the prepared yogurt is mixedinto 2,000 pounds of the cream cheese precursor with agitation. Themixture is cooled to a temperature of 125° F., and then homogenized bysubjecting the mixture to a pressure of about 3,000 PSI at a temperatureof 125° F. for about 5 seconds. The homogenized mixture is thenacidified to a pH of about 4.5 by addition of 25 pounds of Stabilac® 12Natural acid.

The resulting yogurt cream cheese product comprises about 18.74% byweight of butterfat; about 8.85% by weight of milk protein; about0.0613% by weight of cholesterol; about 0.331% by weight of sodium;about 49.77% by weight of water; and about 50.23% by weight of solids.Concerning the protein content of this final product, approximately:40.2% is derived from the nonfat dry milk together with the stabilizer;47.1% is derived from the cream; and 12.7% is derived from the yogurt.The yogurt cream cheese product has a viscosity of about 1,000,000centipoises at a temperature of about 74° F., and yields less than about1% syneresis by weight after 15 hours at about 74° F. to about 75° F.

While the present invention has been disclosed in a presently preferredcontext, it will be recognized that the present teachings may be adaptedto a variety of contexts consistent with this disclosure and the claimsthat follow. For example, the process shown in the figures and discussedabove can be adapted in the spirit of the many optional parametersdescribed, to yield a variety of products, including, for example,yogurt cream cheese, yogurt neufchatel cheese, and yogurt low-fat creamcheese.

1. A process for making a yogurt cream cheese product comprising stepsof: providing a milkfat fluid having an initial butterfat content level;pasteurizing said milkfat fluid to yield a pasteurized milkfat fluid;providing a yogurt, and combining said yogurt with said pasteurizedmilkfat fluid to yield a combined precursor; and homogenizing andacidifying said combined precursor; yielding a yogurt cream cheeseproduct.
 2. The process of claim 1 in which said milkfat fluid includescream.
 3. The process of claim 1 in which said initial butterfat contentlevel is between about 33% to about 50% by weight.
 4. The process ofclaim 1 in which said initial butterfat content level is between about17% to about 33% by weight.
 5. The process of claim 1 in which saidinitial butterfat content level is between about 10% to about 17% byweight.
 6. The process of claim 1 including the step of adjusting saidinitial butterfat content level.
 7. The process of claim 1 including thesteps of providing culture bacteria, and culturing said milkfat fluidwith said culture bacteria.
 8. The process of claim 1 including thesteps of providing a stabilizer, and adding said stabilizer to saidmilkfat fluid.
 9. The process of claim 1 in which said yogurt includeslive culture bacteria.
 10. The process of claim 1, including the step ofadding live culture bacteria to said combined precursor.
 11. The processof claim 1, in which the step of homogenizing said combined precursor iscarried out at an elevated pressure.
 12. The process of claim 1, inwhich said step of acidifying said combined precursor results in a pHbetween about 4.1 and about 5.0.
 13. The process of claim 1, includingthe step of agitating said yogurt cream cheese product in the presenceof an inert gas at an elevated pressure.
 14. The process of claim 1 inwhich said pasteurized milkfat fluid includes retained whey from saidmilkfat fluid.
 15. The process of claim 1 in which said pasteurizedmilkfat fluid is not homogenized.
 16. The process of claim 1, in whichsaid yogurt is made by steps including: providing milk; pasteurizingsaid milk to yield pasteurized milk; cooling said pasteurized milk to abacteria culture temperature; and adding live culture bacteria to saidpasteurized milk; yielding yogurt.
 17. The process of claim 1, in whichsaid yogurt constitutes between about 10% by weight and about 40% byweight of said yogurt cream cheese product.
 18. The process of claim 6in which said step of adjusting said initial butterfat content levelyields a butterfat content level between about 10% to about 50% byweight.
 19. The process of claim 7 including the step of pasteurizingsaid milkfat fluid before said culture bacteria substantially digestsaid milkfat fluid.
 20. The process of claim 7 including the step ofpasteurizing said milkfat fluid within about 60 minutes to about 90minutes after adding said culture bacteria to said milkfat fluid. 21.The process of claim 10 including prior to combining said yogurt withsaid pasteurized milkfat fluid, the step of cooling said pasteurizedmilkfat fluid to a bacteria culture temperature.
 22. The process ofclaim 10, including the step of culturing said bacteria in said combinedprecursor prior to homogenizing said combined precursor.
 23. The processof claim 11 in which said pressure is between about 2,000 pounds persquare inch and about 4,000 pounds per square inch.
 24. The process ofclaim 13 in which the temperature of said yogurt cream cheese product isadjusted to between about 70° F. and about 90° F. prior to beginning thestep of agitating.
 25. The process of claim 18, in which following saidstep of adjusting, said milkfat fluid includes by weight about 34.5% toabout 50% butterfat, about 3% to about 7% protein, and about 59% toabout 42% water, with the balance constituted by other milk solids. 26.The process of claim 13 in which the temperature of said yogurt creamcheese product is adjusted to between about 60° F. and about 70° F.during the step of agitating.
 27. The process of claim 25, in which atleast about 40% of the milk protein is derived from said milkfat fluidand said yogurt.
 28. The process of claim 27, in which at least about50% of the milk protein is derived from said milkfat fluid and saidyogurt.
 29. The process of claim 25, in which the viscosity of theyogurt cream cheese is adjusted to within a range of between about1,000,000 centipoises and about 3,000,000 centipoises at about 74degrees F.
 30. The process of claim 25, carried out in such a manner sothat the yogurt cream cheese: comprises between about 8% by weight andabout 35% by weight of total butterfat; comprises between about 10% byweight and about 40% by weight of yogurt; and has a viscosity within arange of between about 1,000,000 centipoises and about 3,000,000centipoises at a temperature of about 74 degrees F.
 31. The process ofclaim 25, carried out in such a manner so that the yogurt cream cheese:comprises between about 10% by weight and about 26% by weight of totalbutterfat; comprises between about 10% by weight and about 40% by weightof yogurt; and has a viscosity within a range of between about 1,000,000centipoises and about 3,000,000 centipoises at a temperature of about 74degrees F.
 32. The process of claim 25, carried out in such a manner sothat the yogurt cream cheese: comprises between about 23% by weight andabout 26% by weight of total butterfat; comprises between about 10% byweight and about 40% by weight of yogurt; and has a viscosity within arange of between about 1,000,000 centipoises and about 3,000,000centipoises at a temperature of about 74 degrees F.
 33. The process ofclaim 25, carried out in such a manner so that the yogurt cream cheeseproduct: comprises between about 25% by weight and about 26% by weightof total butterfat; comprises between about 10% by weight and about 40%by weight of yogurt; and has a viscosity within a range of between about1,000,000 centipoises and about 3,000,000 centipoises at a temperatureof about 74 degrees F.
 34. The process of claim 30, carried out in sucha manner so that the yogurt cream cheese product comprises between about14% by weight end about 22% by weight of yogurt.
 35. The process ofclaim 31, carried out in such a manner so that the yogurt cream cheeseproduct comprises between about 14% by weight and about 22% by weight ofyogurt.
 36. The process of claim 32, carried out in such a manner sothat the yogurt cream cheese product comprises between about 14% byweight and about 22% by weight of yogurt.
 37. The process of claim 33,carried out in such a manner so that the yogurt cream cheese productcomprises between about 14% by weight and about 22% by weight of yogurt.38. The process of claim 13, carried out in such a manner so that theyogurt cream cheese product has a viscosity within a range of betweenabout 500,000 centipoises and about 1,500,000 centipoises at atemperature of about 74 degrees F.